Dow Jones Industrial Average Slumps Amid OPEC Uncertainty

2 Biotechs Down More Than 50%; Plus, 3 Stocks Rallying on Earnings

The DJIA is trading in the red, as optimism toward OPEC's output agreement fades

The Dow Jones Industrial Average (DJIA) is struggling at midday, as stocks cool after an oil-backed rally on Wednesday. Equities are taking their bearish cues from fluctuating oil prices, with traders questioning the legitimacy of the Organization of Petroleum Exporting Countries' (OPEC) output agreement-- though November-dated crude futures have swung higher at last check, up 0.5% at $47.31 per barrel. Elsewhere, a smaller-than-expected increase in weekly jobless claims and an upwardly revised second-quarter gross domestic product (GDP) reading have seemingly sparked chatter of a December rate hike, as Wall Street digests a busy day of speeches from Fed members. Meanwhile, Apple Inc. (NASDAQ:AAPL) is also weighing on the Dow after a negative analyst note.

Among the stocks with unusual option volume is Chinese e-tailerAlibaba Group Holding Ltd (NYSE:BABA), as the stock sinks 3.5% to $104.96, on reports rival Wal-Mart Stores, Inc. (NYSE:WMT) is in talks to buy a stake in India-based e-commerce firm Flipkart. BABA options were last seen trading at 1.6 times the normal intraday pace, and traders are mostly taking a short-term approach. More specifically, the weekly 9/30 series accounts for five of the six most popular strikes, as traders on both sides of the aisle place bets before the options expire at the close tomorrow. Today's setback aside, BABA has been impressive on the charts in recent months.

Looking at the top gainers on the Nasdaq, travel site Expedia Inc (NASDAQ:EXPE) is continuing its strong performance of late. With today's 2.3% gain to trade at $118.62, the stock has now added more than 11% in the third quarter. Year-to-date, however, EXPE remains 5% below breakeven.

Fitbit Inc (NYSE:FIT) is underperforming on the Big Board today, sliding 8.5% to $15.28, following a downgrade at Pacific Crest -- which cited a "disappointing start" for one of the company's newest products. While FIT is still 25% higher over the past three months, the shares are on the verge of closing below their formerly supportive 40-day moving average for the first time since late July.

The CBOE Volatility Index (VIX) has gained 0.3 point, or 2.6%, at 12.71.

Today's put/call volume ratio on the SPDR S&P 500 ETF Trust (SPY) is 1.74, with puts outpacing calls by a healthy margin. The SPY was last seen 0.7 point, or 0.3%, lower at $215.99.